|
THE
WORLD TRADE CENTER COLLAPSE
Questions & Answers
Implosionworld.com
has received numerous inquiries from around the world requesting
information and commentary relating to the terrorist attacks
of September 11th, 2001, and specifically the felling of the
World Trade Center towers. We have been contacted by media outlets,
structural engineers, schoolteachers, conspiracy theorists and
many others who are searching for answers and some “perspective”
regarding these significant events that have evoked deep emotions
and undoubtedly changed our world forever.
The
editors of implosionworld.com have created this page to answer
a few of the most frequently asked questions that fall within
our area of knowledge and expertise. But first we’d like
to be clear in stating that any conversation relating to “implosions”
and what causes structures to fail is undertaken with reverence
and respect to those who perished as a result of this event.
As many of our frequent web visitors are aware, Implosionworld.com’s
offices are located close to New York City, and several of our
employees were personally touched by this tragedy. Our thoughts
and prayers remain with the families of those lost and injured,
and our intent here is to help foster a constructive base of
knowledge and understanding through education, while dispelling
false rumors related to the attack.
DID THE WORLD TRADE CENTER TOWERS ACTUALLY “IMPLODE”?
No. They collapsed in an uncontrolled fashion, causing extensive
damage to surrounding structures, roadways and utilities. Although
when viewed from a distance the towers appeared to have telescoped
almost straight down, a closer look at video replays reveal
sizeable portions of each building breaking free during the
collapse, with the largest sections--some as tall as 30 or 40
stories--actually “laying out” in several directions.
The outward failure of these sections is believed to have caused
much of the significant damage to adjacent structures, and smaller
debris caused structural and cosmetic damage to hundreds of
additional buildings around the perimeter of the site.
WHY
DID THEY COLLAPSE?
Each 110-story tower contained a central steel core surrounded
by open office space, with 18-inch steel tubes running vertically
along the outside of the building. These structural elements
provided the support for the building, and most experts agree
that the planes impacting the buildings alone would not have
caused them to collapse. The intense heat from the burning jet
fuel, however, gradually softened the steel core and redistributed
the weight to the outer tubes, which were slowly deformed by
the added weight and the heat of the fire. Eventually, the integrity
of these tubes was compromised to the point where they buckled
under the weight of the higher floors, causing a gravitational
chain reaction that continued until all of the floors were at
ground level.
DID
THE TERRORISTS PLANT ANY BOMBS IN THE BUILDINGS IN ADVANCE TO
GUARANTEE THEIR DEMISE?
To our knowledge there is no evidence whatsoever to support
this assertion. Analysis of video and photographs of both towers
clearly shows that the initial structural failure occurred at
or near the points where the planes impacted the buildings.
Furthermore, there is no visible or audible indication that
explosives or any other supplemental catalyst was used in the
attack.
HOW
DOES THIS EVENT COMPARE WITH A NORMAL BUILDING IMPLOSION?
The only correlation is that in a very broad sense, explosive
devices (airplanes loaded with fuel) were used to intentionally
bring down buildings. However it can be argued that even this
vague similarity relates more to military explosive demolition
than to building implosions, which specifically involve the
placement of charges at key points within a structure to precipitate
the failure of steel or concrete supports within their own footprint.
The other primary difference between these two types of operations
is that implosions are universally conducted with the utmost
concern for adjacent properties and human safety---elements
that were horrifically absent from this event. Therefore we
can conclude that what happened in New York was not a “building
implosion.”
ARE
THERE ANY PLANS TO EXPLOSIVELY DEMOLISH THE REMAINS OF NEARBY
BUILDINGS?
Not at this time, and probably not in the future. Engineering
officials have expressed concern over the risk of causing additional
damage to sensitive underground liabilities such as subway tunnels
and below-grade retaining walls. Therefore any future demolition
activities will likely be performed piecemeal, using heavy equipment.
Editor's
update 12/20/01- With the removal of the 8-story U.S. Custom's
House yesterday morning, all condemned structures have now been
removed from the site. Explosives were not used in these operations.
HOW
HAVE THE EXPLOSIVES-USING INDUSTRIES BEEN AFFECTED?
Immediately following the attack, the U.S. Department of Alcohol,
Tobacco and Firearms (ATF) and other international regulatory
agencies suspended all transportation and delivery of explosives.
This caused temporary disruptions within the quarrying and construction
industries as well as the postponement of several high-profile
explosive demolition projects in the United States and Europe
(although it should be noted that all of these projects, including
the DFW Hyatt Hotel, Jordan Thorpe Towers and Roby-Huntington
Bridge, among others, were eventually rescheduled and successfully
completed in October 2001). In the interim, the ATF issued warnings
related to the reporting of suspicious activities near explosives
storage and distribution areas, as well as an advisory
regarding the transportation of hazardous materials and the
commencement of non-routine
visits to persons and locations where explosives are stored
and used. It can also be reasonably assumed that other safeguards
will be implemented that are not announced to the public.
HOW
WILL THIS EVENT AFFECT EXPLOSIVE DEMOLITION IN THE FUTURE?
Although the full effect of these events remains to be seen,
certain changes are already taking place. In the short term
there will be tighter security on jobsites and stricter
regulations on the use and transportation of explosives
as mentioned above. Liability insurance will also likely become
an issue, as an anticipated rise in rates may affect the economic
viability of explosive demolition as an alternative to conventional
methods. But perhaps the largest question involves public perception
and society’s continued acceptance of building implosions
in general, particularly as “entertainment.” It is
recognized that there will always be select situations where
explosive demolition is viewed as the safest and most effective
way to raze a given structure. However industry experts will
be watching to see whether the compelling visual allure of these
events continues to be successfully exploited as promotional
spectacle like many are today, or if the thunderous noise, energy
and dust emanating from giant structures crashing to the ground
bring forth latent mental images of terror and suffering. History
tells us that strong emotions dissipate with time, and that
they eventually come to pass. But history has never experienced
an event--or an era--quite like this.
October
2001
|
|
|
©Brent
Blanchard / Protec
|
|
